British Airways staff have criticised passengers as "smelly and annoying" and condemned the opening of Heathrow's Terminal 5 as a disaster.

According to comments on a Facebook page created by "London Gatwick Ground Staff", their biggest hate is travellers who put boarding passes in their mouths before handing them over at the departure gate.

One staff member criticises smelly passengers and celebrity fliers, while another vents his anger at Americans.

The postings on the social networking site, which is a closed group that only BA staff can join after being vetted by the organisers, include one by an apparent employee called "Deepa", who moans (complete with vernacular grammar and spellings): "They ask which gate with their stupid American accent – aaargggh!! Its soooo annoying!!!!" Another member of staff, named as "Suely", complains about "smelly passengers" and "snotty" celebrities.

The site also lampoons the chaotic opening of Terminal 5 (T5) in March.

It contains a link to a game in which Willie Walsh, BA's chief executive, is shown struggling with the baggage system at Terminal 5 and being hit by a succession of trolleys.

More than 36,000 passengers were hit by "multiple problems" on T5's day of opening. Flights were cancelled, massive queues built up and 23,000 bags had to be sorted by hand after the long-awaited opening of the £4.3bn terminal descended into chaos.

Disillusioned BA staff have also uploaded a video of a song containing the lyrics: "You can shove this terminal up your arse."

The revelations came two weeks after 13 Virgin Atlantic staff were sacked after describing their passengers as "Chavs" on their Facebook page. BA has launched an investigation into the postings. A spokesman refused to discuss whether disciplinary action would be taken. He said: "We will be talking to the individuals concerned about their disappointing and unwise comments, which are totally unrepresentative of the vast number of hard working ground staff we employ at Gatwick."

A scathing report by MPs today chimes with some of the BA employees' views, concluding that a catalogue of blunders turned T5's opening into a "national embarrassment".

The Commons transport select committee put the blame jointly on British Airways and on the airport operator BAA, which it said should be stripped of its monopoly over airports in the South of England.

It said: "What should have been an occasion of national pride was in fact an occasion of national embarrassment. When the baggage system failed, luggage piled up to such an extent that it was transported by road to be sorted off-site. According to BA, 23,205 bags required manual sorting before being returned to their owners."

The MPs blamed the shambles on inadequate communication between BA and BAA and poor staff training by BA. Louise Ellman, the committee's chairman, said: "We were struck by how much 'hoping for the best' BAA had engaged in prior to the opening of T5.

"We are glad BAA and BA have now taken measures to improve their communications but it is deeply regrettable these steps were not taken before the opening."